About halfway through the flight, the pilots of ASH1002
stopped responding to air traffic control
communications. While out of radio communications, the
flight passed over its destination airport, General
Lyman Field (ITO),
Hilo, Hawaii, at cruise altitude.

After
traveling 26 nautical miles beyond ITO on a constant heading,
the flight crew resumed radio communications with air traffic
control and returned to land at ITO. The airplane was not
damaged and the captain, first officer, flight attendant, and 40
passengers were not injured during the event. The flight was
conducted in accordance with 14 Code of Federal Regulations
(CFR) Part 121. An instrument flight rules (IFR) flight plan was
on file and activated during the flight. The first officer was
assigned the role of the flying pilot.

The flight
crew's communications with air traffic control during departure
from Honolulu
had been routine. About 0930, the captain had contacted Honolulu
Control Facility (HCF) and informed the facility that ASH1002
was climbing through 11,700 feet to its cruise altitude, Flight
Level 210.

HCF
acknowledged this transmission and cleared the flight to proceed
direct to the PARIS intersection,
near the big
island
of Hawaii.
The captain acknowledged the clearance but the flight did not
change course. About 0933, HCF again cleared ASH1002 direct to
the PARIS
intersection. The captain acknowledged the instruction a second
time, and the flight's track turned toward
PARIS. Both pilots later stated that soon
after they received this clearance they inadvertently fell
asleep in the cockpit.

The
captain stated, "Working as hard as we had, we tend to relax."
He further stated, "We had gotten back on schedule, it was
comfortable in cockpit, the pressure was behind us. The warm
Hawaiian sun was blaring in as we went eastbound. I just kind of
closed my eyes for a minute, enjoying the sunshine, and dozed
off." The first officer said he entered a sleep-like state from
which he could "hear what was going on, but could not comprehend
or make it click."

At 0940, as the
flight was crossing the island of Maui.
HCF instructed ASH1002 to change radio frequencies, but the flight crew
did not respond. For the next 18 minutes, HCF attempted to contact
ASH1002, but received no replies. About 0951, ASH1002 reached the PARIS intersection and turned southeast toward
the Hilo VOR.

The HCF controller
who was handling the flight asked another HCF controller to contact
ASH1002 on a different radio frequency. The other controller made the
attempt, but received no reply. At 0955, ASH1002 crossed the Hilo VOR.
It continued southeast at Flight Level 210, crossed the northeast coast
of Hawaii
and flew out over the open ocean.

HCF asked another
Go! flight crew to try to contact ASH1002 on a company radio frequency.
The flight crew made the attempt, but received no reply. In addition, a
Continental Airlines flight attempted to contact ASH1002 on an emergency
frequency, but was also unsuccessful.

About this time,
the first officer awoke. Realizing the airplane was off course, he noted
that 4,500 pounds of fuel remained. He estimated that this amount would
last an hour and a half. Next, the first officer woke the captain and
told him air traffic control was attempting to contact the flight. About
0958, the captain contacted HCF, stating, "[unintelligible] HCF ten zero
two."

HCF asked the
captain if the flight crew was experiencing an emergency situation, and
the captain replied, "No, we must have missed a handoff or missed a call
or something." HCF then issued vectors for ASH1002 to return to ITO, and
the flight crew complied. The flight arrived at 1015.

As ASH1002 arrived
at ITO, air traffic controllers directed the captain to contact them by
telephone. After the airplane was parked at the gate, the captain
instructed the first officer to prepare the airplane for its next flight
while he disembarked and called the FAA. The captain told FAA personnel
by telephone that ASH1002 had lost radio communications because the
flight crew had selected an incorrect radio frequency. FAA personnel
informed the captain that they intended to report the incident to Mesa
Airlines.

After his
telephone conversation with the FAA, the captain returned to the
airplane and had a discussion with the first officer about whether they
should operate the next flight. The pilots agreed that it would be safe
for them to do so because they were feeling very alert as a result of
the incident. According to company records, they departed ITO for HNL on
the incident airplane at 1028, using the call sign ASH1044. During the
flight to HNL, the pilots discussed the incident further and they
decided to remove themselves from duty upon arrival. ASH1044 arrived at
HNL at 1118.

After parking at
the gate, the captain arranged for a reserve crew to operate the next
flight he had been assigned to fly with the first officer. Next, the
captain called the airline?s scheduling office to inform the company
that both he and the first officer were removing themselves from duty
for the rest of the day. The captain's telephone call was transferred to
a chief pilot who requested an explanation for the flight crew's
decision. The captain declined to provide an explanation on the
telephone. A few hours later, however, he submitted a written report to
Mesa Airlines explaining that he and the first officer had fallen asleep
on ASH1002 during the cruise phase of flight.

The captain, age
53, held an airline transport pilot (ATP) certificate for airplane
multiengine land, and commercial privileges for airplane single-engine
land. He possessed type ratings in the following airplanes: BA-3100,
BE-300, BE-1900, CL-65, DHC-8, and SA-227. His pilot certificate carried
the following limitation, "BE-300, BE-1900, Second-In-Command Required."

Company records
indicated that the captain had completed his last recurrent training on
July 19, 2007, his last line check on December 5, 2007, and his last
proficiency check on January 4, 2008.

The captain had
worked as an airline pilot for over 20 years. Air
Midwest hired him as a pilot on October 7, 1987. Mesa
Airlines acquired Air Midwest in 1991, and the captain became an
employee of Mesa Airlines on September 3, 1997. At that time, he was a
captain on the Beech 1900D. On September 16, 1997, he transitioned to
the position of captain on the de Havilland DHC-8, and on July 23, 1998,
he transitioned to the position of captain on the CL-65.

The captain's
statements and company records indicated that he had between 20,000 and
25,000 hours of flight experience, including 8,000 hours as
pilot-in-command in the CL-65. The captain reported 830 flight hours in
the last 12 months, 415 hours in the last 6 months, 207 hours in the
last 90 days, 76 hours in January 2008, and 38 hours during the period
February 1-12, 2008.

The captain
resided in Kennett,
Missouri and had been based in the company's Nashville,
Tennessee
domicile. At the time of the incident, he was temporarily assigned to Mesa's Kahului,
Hawaii domicile. This temporary
assignment had begun January 13, 2008 and was originally scheduled to
end February 9, 2008. Near the end of this period, however, the
temporary assignment was extended for an additional 28 days.

The captain's
activities in the three days preceding the incident were as follows:

? On Sunday,
February 10, 2008, he reported for duty at OGG at 0740, flew 4 legs and
went off duty at OGG at 1445. He reported going to sleep between 2030
and 2100, and described his quality of sleep as "probably good."

? On Monday,
February 11, 2008, the captain awoke at 0400. He reported for duty at
OGG at 0540, and was paired with the incident first officer. He and the
first officer flew 8 flights together. He went off duty at OGG at 1445.
He could not recall his activities the rest of the day, but reported
going to sleep between 2030 and 2100. He described his quality of sleep
as "probably good."

? On Tuesday,
February 12, 2008, the captain awoke at 0400. He bought breakfast at a
fast food restaurant and reported for duty at OGG at 0540. The captain
was paired with the incident first officer. Their first flight was
slightly delayed because the flight attendant arrived late. The captain
and first officer operated 8 flights together and the captain went off
duty at OGG at 1447.

The captain
returned to his hotel and spent two hours trying to obtain a new rental
car reservation, as his rental car agreement was about to expire. He was
unsuccessful, so he then ran some errands, bought dinner at a fast food
restaurant, and returned his car about 1930. He used his hotel's shuttle
service to return to his room, and arranged for the incident first
officer to pick him up and drive him to work the next day. He reported
going to bed between 2000 and 2100, and he described his quality of
sleep as "pretty good."

? On Wednesday,
February 13, 2008, the captain awoke at 0400. The incident first officer
arrived later than he expected, so the captain was unable to buy
breakfast on the way to the airport. The captain reported for duty at
OGG at 0540. Because of a flight attendant scheduling error, the crew?s
first flight departed 30 minutes late. The captain shared a package of
cookies with the first officer on the airplane, and flight crew was back
on schedule as they departed HNL at 0916 on the incident flight.

The captain stated
that he had never before inadvertently fallen asleep during a flight,
but he had intentionally napped in the cockpit during previous flights.
He said he had intentionally napped in flight about once per week during
his temporary assignment in Hawaii, and that his naps normally lasted
about 20 minutes. Furthermore, he stated that he had napped more often
than once per week prior to beginning his temporary assignment in Hawaii. A Mesa
first officer who had flown with the captain in the continental U.S. confirmed
that the captain had napped on flights they had operated together. Mesa?s senior director of
flight operations said that, before the incident, he had been unaware of
the captain's in-flight naps.

The first officer,
age 23, held a commercial pilot certificate for airplane single-engine
land, airplane multiengine land, and instrument airplane. He possessed
type ratings for G-1159 and CL-65 airplanes. His type rating on the
CL-65 was for "second-in-command privileges only" and it contained a
limitation stating that he could only perform circling approaches in
visual meteorological conditions (VMC).

Mesa Airlines had
hired the first officer on May 8, 2007. He had completed initial ground
training for the CL-65 on June 10, 2007, initial flight training on July
14, 2007, and initial operating experience (IOE) on September 1, 2007.

According to
company records, the first officer had 1,250 hours of flight experience,
including 500 hours in the CL-65. He had accumulated 240 hours in the
last 90 days, 80 hours in the preceding 30 days, and 38 hours during the
period February 1-12, 2008.

The first officer
was assigned to the airline?s Kahului domicile, and he resided nearby in
Kahului. The first officer's activities in the three days preceding the
incident were as follows:

? On Sunday,
February 10, 2008, the first officer was off duty and he visited with
friends on the big island of Hawaii.
He reported that he returned to Maui
about 1430 and went to sleep by 2200. He could not recall his quality of
sleep.

? On Monday,
February 11, 2008, the first officer reported waking between 0450 and
0500. He reported for duty at OGG at 0540 and was paired with the
incident captain. After completing 8 legs with the captain, the first
officer went off duty at OGG at 1445. He reported going to sleep by
2200, and could not recall his quality of sleep.

? On Tuesday,
February 12, 2008, the first officer awoke between 0450 and 0500. He
reported for duty at OGG at 0540 and was again paired with the incident
captain. He completed 8 legs and went off duty at 1447. After going off
duty, he engaged in outdoor sports and had dinner about 1730. He
reported going to sleep at 2130, and described his quality of sleep as
"good."

? On Wednesday,
February 13, 2008, the first officer awoke between 0450 and 0500. He had
a pastry for breakfast. He reported for duty at OGG at 0540 and was
again paired with the incident captain.

First Officer's
Previous In-Flight Sleeping Behavior

The first officer
stated that he had never fallen asleep during a flight before.

Operational
Stressors Reported by the Flight Crew

The flight crew
reported several operational stressors in the days before the incident.
The pilots reported (and company managers confirmed) that the airplane
they had operated on February 11 had a partially functioning flight
management system. This forced the pilots to navigate using VOR radials
rather than flying directly between navigational waypoints. As a result,
they were unable to accept some typically ATC clearances. They reported
that this caused them to experience increased workload.

On February 12,
the flight crew was again assigned the airplane with the partially
functioning flight management system. After a few flights, however, they
were assigned a different airplane with a fully functioning flight
management system. Also on the morning of February 12, the flight
attendant assigned to work their first flight arrived late, placing them
slightly behind schedule. The flight crew had to rush to make up the
time on subsequent flights.

On February 13,
the crew learned that the flight attendant assigned to their first
flight had been scheduled in error. The flight crew made arrangements
for a replacement flight attendant, but this delayed their departure by
30 minutes. The flight crew had to rush during their first three flights
of the day to make up the delay.

The captain's most
recent FAA first-class medical certificate was issued on December 18,
2007, and it bore the limitation "must wear corrective lenses while
exercising the privileges of this certificate."

The captain
described his health as "fair." He stated that he was prone to
respiratory illnesses, but had not experienced any the week before the
incident. He reported high blood pressure and took a combination
prescription medication (trandolapril/verapamil 4/240) to control it. He
stated that he had not taken any medications, prescription or
nonprescription, that might have affected his performance.

The captain was a
regular smoker, and reported smoking about 25 cigarettes per day. He
reported smoking his last cigarette before departure on his first flight
of the day, at 0655. He stated that he carried nicotine gum when he was
working, but could not recall whether he had used it on the morning of
the incident. He stated that he drank alcohol, but had not consumed any
in the 24 hours before the incident.

The captain said
he had been feeling "burned out" in recent months. He attributed this to
his working conditions, less time off, and frequent amendments to his
schedule. He said that he had encountered these challenges before, but
had recently been finding it more difficult to cope with them. He stated
that he had applied for the temporary assignment in Hawaii in search of some relief, but had found the work in
Hawaii no easier because he had to fly 8 legs
per day with few breaks. This minimized his ability to obtain coffee,
eat, and smoke cigarettes.

The captain said
that he snored loudly at night, and that he had raised the issue with
his personal physician in December 2007. He stated that his physician
had told him to lose weight, eat less salt, and relax. He stated that,
during his stay in Hawaii
he had lost 15 pounds through exercise and was "sleeping better."

The captain said
he had been having difficulty adjusting to day to day life in
Hawaii, and that he would have preferred to
return to the mainland rather than have his temporary duty assignment
extended.

After the
incident, the captain underwent an evaluation by a sleep medicine
specialist and was diagnosed with severe obstructive sleep apnea, a
condition associated with reduced sleep quality, daytime fatigue, and,
in severe cases, cognitive dysfunction. The evaluating physician wrote
that the captain?s condition provided "an etiology for significant
fatigue".

The first
officer?s most recent FAA first class medical certificate was issued on
February 2, 2007, and contained no limitations.

The first officer
described his health as "good," and he said he felt well on the morning
of the incident. He stated that he did not normally take prescription
medication, and that he had not taken any medication, prescription or
nonprescription, in the 72 hours before the incident.

The first officer
stated that he did not use tobacco products. He reported that he did
drink alcohol, and last consumed some about 1700 the day before the
incident, when he drank one beer.

The first officer
said he was not experiencing any stress related to his personal life on
the morning of the incident, nor had he experienced any recent changes
in his health or personal life. He stated that, in the past year, he had
experienced a positive change in his finances as a result of his
employment with Mesa Airlines.

On the morning of
February 14, 2008, Mesa Airlines senior director of flight operations
asked the captain and first officer to provide a urine specimen that
could be tested for drug testing and they complied. These tests yielded
no evidence of drug use. The senior director told investigators he did
not request urine specimens until the day after the incident because he
did not receive information describing the nature of the incident until
the evening of February 13, 2008.

An NTSB Survival
Factors Specialist interviewed the incident flight attendant on March
27, 2008. During an interview the flight attendant stated that she had
flown 4 legs with the flight crew, and that neither of them appeared
tired. She described the captain's preflight as being "very short", and
was concerned that on the first of the 4 legs that the flight crew did
not provide a sterile cockpit signal ("ding"); she also revealed that
she did not receive the sterile cockpit signal on the second leg. She
did not recall and ?couldn?t say? whether she had received the sterile
cockpit signal on the 3rd and 4th legs of the trip.

The flight
attendant reported that the incident flight was between 37 to 40 minutes
in length, and that while she was wearing a watch she did not recall if
she looked at it after take-off on the incident flight. She indicated
that she did not notice anything unusual about the flight and did not
sense that it was longer than usual, nor did she feel that there was
anything "unsafe." She reported that she is normally aware of the
flight?s position and how much longer the flight will take by the flight
crew's announcement that they are descending.

When the
specialist asked the flight attendant if she is normally aware of the
terrain that the airplane is flying over, the flight attendant stated
that she may notice their location during the middle of the flight
because she is in the cabin and can see out of passenger windows. When
she is on her jump seat she is not able to see the terrain because the
only window available is on the service door.

When asked when
she would contact the flight crew the flight attendant responded that
she did not normally contact the flight deck crew during a flight, but
she would if it was an unusually long flight or if she had a passenger
problem or a safety-related issue.

When questioned by
the specialist about her training for an "incapacitated pilot," the
flight attendant replied that if she was contacted by the other pilot
and admitted to the flight deck she was trained on how to pull out the
pilot's seat. The flight attendant revealed that she had no access to
the flight deck unless admitted by a pilot.

She
was asked what she would do if she thought the flight was
going on longer than she thought was normal and had not
heard from the pilots. She said that she would use the
interphone to contact the flight crew. If the interphone did
not work, she would use her cell phone to call someone.

The
flight attendant described the company's Crew Resource
Management (CRM) training as "pretty thorough". She
indicated that the training included information about crew
introductions, procedures for emergencies, and safety issues
with the crew. She was asked about contacting the cockpit
during sterile cockpit and she said sterile cockpit was a
critical time of flight and she would not contact the flight
crew during that time unless it was an emergency, such as a
passenger problem, fire, or other safety-related problem.

On June 9, 2006, Mesa Airlines launched Go! Airlines as
a wholly-owned subsidiary providing scheduled service
between HonoluluInternationalAirport and airports in Hilo, Kahului, Kona, and Lihue, Hawaii.
According to
Mesa?s senior director of
operations, Go!?s initial fleet consisted of two
Canadair Regional Jets. Four months later,
Mesa
added three additional regional jets to the fleet. Go!
had maintained a fleet of five regional jets and a
workforce of about 60 pilots from then until the day of
the incident.